Is This An Exposed Zinc Core 1988 Lincoln?

I see Split Plating and maybe heat exposure exposed the rest of the zinc core? https://www.error-ref.com/split-plating/

This looks legit at first glance, you may have to test the different coloured regions with an XRF to confirm. It's a type of incomplete plating. In Canada we would call something like this a "diffuse plating error", but I'm not sure what the terminology is in the States.

https://www.coinworld.com/news/us-c...ive-pla.html

Is it worth anything?

Dearborn, look again. This is beyond the split plating that's very often seen, and goes into incomplete/insufficient plating category.

Here is a coin with a similar error that I found in Canada. Keep in mind that the process of making a penny planchet is different between Canada and the USA, so you cannot apply the manufacturing process quoted in that thread to American coins.

https://goccf.com/t/481794

Modern Canadian errors are uncommon due to the level of quality control at the Mint, but I don't know about American, whether they are common or scarce. To me, American errors seem more common than Canadian, but the US Mint also deals with more volume. I can't give you a price point for this item.

This may be a question for Mike Diamond. Is he still active on this forum?

It's a case of solid-state diffusion. This occurs after the coin leaves the Mint and is not an error.

Man @mikediamond spot on, never knew this thanks!